The number of patients with cardiovascular implantable electronic devices (CIED), including ventricular pacemakers, continues to increase. However, there are no accurate electrocardiographic (ECG) criteria to diagnose acute myocardial infarction (AMI), even if due to acute coronary occlusion (ACO), with a ventricular pacemaker in situ. In this retrospective, multicenter, case-control study the investigators will examine ECG criteria to diagnose ACO in patients with ventricular paced rhythms. During this process, the investigators will also create a database from which investigators will be able to answer multiple additional questions on this population of patients.